The rules about raffles are locally, or maybe state-defined, depending on your location. You might want to start at your town hall and go from there. You might need a license or there may be exceptions that apply, but you really won't know for sure until you check.
NewTreasurer - no you don't have to incoporate. That's an optional process at the state level, which has some valuable benefits.
However, if you already have your 501(c)(3) and are not incorporated, you probably don't want to incoporate now.
Incorporating creates a new business entity and your 501(c)(3) does not transfer. So you'd have to go through the whole process - and pay the filing fee - with the IRS again to be a 501(c)(3) entity.
new treasurer I will answer that question and Critter can let us know if it is different. In reading Critters post I am getting that she means if you are not a 501 then incorporate before you apply for 501. You can be a 501 but not incorporated BUT it is costly to become 501 then incorporate.
"When you stop learning you stop growing."