I LOVED AR and volunteered so much w/ AR that my son's school ended up creating a part-time job so I would keep doing it. It was the best job in the entire school (the kids love u as your the reward/party person). Sadly my son is in middle school now and doesn't have AR but I'll share lots of ideas I did various years.
I would choose a theme for each year. The year of the Olympics I ordered these cheap dog tags that were awarded throughout the school year according to how many AR points they earned. I'm not sure their still around but it was called "Tag-It"....you could order various sizes, shapes, colors and for every 5, 10 points, etc the students would get new tags. These were placed on clips that the students clipped on their backpacks and they were a huge hit. After they earned mile stone AR numbers they'd receive bronze, silver, then gold special tags. I ended up doing that another year it was so popular.
Another big hit w/ the kids was the "Accelerated Reader Wall of Fame". I did this every year. We had a long wall at the entrance of our library and at the beginning of the yr. I'd take each students' photo and then laminate it to whatever shape cutout was our theme. Their picture would move along the wall to the different levels. An example was one year our theme was "Soaring w/ AR" and our mascot was an eagle so it was the biggest level w/ the other levels being falcon, hawk, etc. You could use a theme of "Storming into Reading" and have the rain storm level, blizzard, hurricane, etc.
Another thing we did was have an AR store. Our PTA sponsored it and had a standing committee chair in charge of keeping it stocked w/ goodies the students could come and spend points once a month. She would base items according to the cost - example a dollar a point. She purchase lots of stuff from the Orential Trading so there'd be lots of small point items....but she'd also purchase several big items like ipods, rip sticks, etc. We'd get parent volunteers to take the students to shop once a month....we had this big display cabinet in the main hall so the kids were always looking to see what was there.
It's important to grab the students right off the bat at the beginning of the school year so I would always have some type of "AR Kick Off" contest. Basically, the students (the whole school) had to earn 500 points w/in 6 weeks (easy if u have 400+ students). The reward would be something really fun like the principal kissing a goat, pig....the year of our Olympic theme I had our principal scooter race the assistant principal around our school track. We hammed it up and they dressed up and we played "Rocky" music....the kids talked about that for months. Of course during the kick off contest you make announcements of how many points they've earned once or twice a week and how many more they needed, which I always fudged on so they'd keep reading until the end.
Some of the fun parties I did for students that earned their quarter AR goals.
50's Sock hop w/ a soda fountain giving out coke floats, with it a 50's dress up contest, and dancing contest, sack races
Slip and Slide - this is easy...get plastic tarp u can get at Lowe's or Home Depot, lots and lots of baby shampoo and some play sand....i'd use the sand to keep the tarp in place the w/ a water hose running kept the plastic soaked along w/ baby shampoo for easy sliding.....the kids love this party and I'd end up doing this every year.
Picnic in the park....
Bowling party
Jumpee Jim or big obstacle course....
Hawaiian luau w/ games of hula hooping, limbo, etc have the kids dress hawaiian for that day, hula hop sack races
I'd always take pictures during the parties which I'd place on the AR bullentin board for a week or so....the kids loved seeing their pictures up...then I'd give them to the year book person...which would end up giving AR lots of pages in the year book too.
Another thing I did sometimes during the year is have classroom competitions. Basically each class in a grade competed for a month for a pizza party...a couple of times a week i'd give an update as to how much each class was earning for that month and had it on a bullentin board reserved just for AR i kept decorated. At the end of that month I'd announce the winner and arrange the pizza party for their classroom.
Another year instead of the monthly pizza party competitions I purchased a life size Elvis board cut out...our theme was "Rock - n- Roll Reading" and which ever class earned the most ar points for that month would get elvis by their classroom door for the month...I had an Elvis for each grade so that it was fair....that was a big hit w/ the kids that year. The principal loved it when she would be showing various people around the school during the year and there were these life size Elvis's all around the school.
One thing I did every year for our "Wall of Fame" was at a special location at the end there was an 8x10 picture. The person that earned the most AR points for the entire year would get his/her picture taken and I placed it in that frame along w/ the # of points....this would be up for the entire NEXT school year until the end of that year a new winner earned the award.
I didn't mean for this to be so long but AR is an awsome thing if u can make it fun for the kids and grab their attention. One thing I successfully had our school change w/ AR was go to quartly goals instead of yearly. If a child got really behind on their goal...when it was a yearly one they would usually give up but if they had a fresh start each quarter then they seemed to be determined not to miss the next fun party. Good luck...but mostly have fun w/ it.