Oh I am so glad you haven't SI in a month! That is great!
Ummm...ok suggestions.

Go outside for a walk (hopefully not too hot yet)

Play some games, like the games forum here is fun, or maybe watch silly vids on the computer...(like on websites which I wont write the name coz it's probably considering promoting, lol)

Crank up the music and dance around all goofy since u are alone, no one will see!

Dye your hair? (i did to myself that this weekend when I was down. that was interesting)

Make yourself a picnic lunch/breakfast depending on where you are at?

Punching a pillow works if you are feeling destructive...or even tearing up paper into shreds? I have punched a box before too? (u don't hurt your hand like if u hit something that doesn't give)

I hope these aren't too lame. I know how hard it is to even get the motivation to do stuff when you are feeling down.

I tried to think of relatively free/cheap things too since I don't usually have a lot of money to go shopping, or see a movie, etc.