Outside. October means the perfect weather! Not too hot, and not too cool.
Have huge banners saying "Homecoming!!" or "GO (team name here) GO!". Homemade banners are always fun, and you could even turn it into a contest. Have a few judges to find out who made the best banner.
Have a huge bonfire, and have someone make a scarecrow/puppet of the other team's mascot or a puppet wearing the other team's shirt and BURN IT! Always fun. Stuff with newspaper, and if you want, put firecrackers in it. Please becareful with this idea.
Music is a must, and get a few energy pumping songs! You want everyone pumped about the party. Make sure it's not loud enough to make some people complain. A DJ, possibly? Just make sure the DJ lets people request music, if they don't, that's just lame!
Balloons with your team's colours would be great. Helium is your best bet, and put them into large clusters and just set them all over the place. Weigh them down with a sandbag.
If you don`t want the entire deal of buying the food, hire a catering business. Might seem like a splurge, but it would be more fun to enjoy the party rather than worry about the food. Let the caters do that!
Make sure everyone is wearing your team colours! If they don't, then hire people to face paint. Or give out free team hats.
Have a costume contest, dance off, limbo contest, karaoke....endless ways to have fun!
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