It has to be at my house, and we're going to watch a movie and order in pizza. What are some other activities we can do?

food fight? haha joke!!! tri-legged, sack racing, ps3, more movies, bowling(?), draw something while blindfolded, outdoor games and stuff!!

Play games like pictionary, trivial pursiut, anything that you can play with groups. Listen to music, play name that tune.

Talk to your folks first and enlist their help (and your neighbours) to have a scavenger hunt. Divide into teams and have some type of prize for whomever comes up with the most items on their list. It doesn't have to be costly at all... a wide ribbon with glittered "Winner" or "Found 'Em" on it and a safety pin on the back may end up someone's treasure.

Have fun!

Interactive games are a good way to go.

as said before, a scavenger hunt throughout your neighborhood would be really fun.