Buy..

A pair of pants/trousers a size too small (it may be for the gym, or just a pair of jeans) and tell yourself in _____ weeks I WILL fit these.

I think this could be very motivational. Especially if it's an expensive pair of bottoms! :) haha.
Has anybody actually done this?

I totally do this.

I also have a bunch of clothes from when I was thinner that I'm still trying to work my way into.  Sometimes it can be frustrating but when you finally get them to look good on you, it's so rewarding :]

sounds like a waste if they don;t fit perfectly after.. especially if i spend like 80 bucks on a pair of pants i want them perfect on my new body..

plus makes me feel down/fat at the time, generally a bad idea for me

plus i like to wear my new clothes when i get them because its exciting. :]

I buy shirts that are too small instead. Pants are tricky to fit right even if it is in your size. Shirts are a little more versitile. :) In fact, I just tried on a shirt that I didn't fit in to 2 months ago and now it looks great! Yay!

I always had a skirt that didn't really fit... it didn't do a thing for me any time before except make me feel guilty (ironically, now I've finally lost all that weight, the skirt and all my other good clothes are practically falling off me and I've never worn any of them in years!) Weight loss is so slow that it's not really a good idea to deliberately get anything way too small - you'd be better off buying something snug and watching it gradually get looser.

I have a ton of clothes waiting in a drawer until I finally fit into them! Personally I find it discouraging to buy clothes that I'm too "fat" to fit into ...

instead, I prefer to put a small amount of money into savings each week, and window shop. If I set a target, i.e. eventually reaching a weight of xxx .. then I can go out and spend all the money on new clothes.

And I know I will have more fun because they will fit and I will look great in them!