Do you have a Booster Membership card? We charge for ours, but you don't have to. You could hand out membership cards with your meeting dates/times/info on them to parents at all your functions.
We also make an effort to attend the various athletic parent group meetings run by the coaches to talk about the Boosters.
Our Boosters also run the Spirit Shack as well as Concessions. We have a sign up date for the coaches to volunteer their parents for game days to help in the Concession stand.....we offer their group a portion of the profits for each game day if they provide the volunteers.
We provide scholarships for our students. Talk to the school counselors about promoting your scholarships. If your school offers a College Night, have a table set-up with information for families about the scholarships your group provides and what the criteria is for applying.
As for Spirit Wear.....I really like the idea of a fashion show.....we have talked about having the students who run announcements in the morning wear some of the spirit wear to showcase it....we have video in each classroom for announcements.
We try to tie in with events already happening in the school. If the Art Department has a Craft show fundraiser, we have a Pancake Breakfast before it.
Last year, we gave away decals with memberships. This year we are handing out magnets with our meeting dates on them. And on all of our membership forms we ask for e-mail addresses so we can send out reminders for our meetings.
Getting parents involved in middle school/high school is so much more difficult than elementary.....everyone has different activities they are involved in. Good Luck. I will check back to see what results you have.