Okai, please help asap. party question!?!

Okai, its my birthday a week tday and my party this Friday.. And i don't know what to do for it! I have no idea what so ever and have left it really late because of recent things that have happened. This year im also cut to a budget, i don't know how mush, under ￡50 i guess due to the recent purchase of a boat and what not. I NEED ideas for a party with me & 3 friends to do in the UK, suitable for the weather in Late feb/Early March. Also i've thought of the sleepover but we have to re-decorate the living room te next day and are re-carpeting the Kitchen the day before os it will be hectic! A sleepover is still an option with something else to go with it and things to do at it.. and help would be great, as soon as possible really. Thankuuh in advance :)