Water fight with friends - get out those Nerf guns
Go to the beach
Movie marathon (get your friends to bring their favourite DVDs)
Go for a long walk or a bike ride
Play board games - Monopoly, Game of Life, Twister, Celebrity Head
Sort through your wardrobe and take all the clothes you don't wear or dont fit to Vinnies or the Salvos
Go to the park with friends and throw a frisbee, kick a footy or play beach cricket
Bake
Have a spa day with your friends and give each other pedicures and manicures
Learn to sew, knit or crochet
Do a jigsaw
Read a book
Get a job
Go to an exercise class (try your local community centre)
Go ice skating or roller skating
Go to the movies - some cinemas have cheap tickets on Tuesdays
Go to the zoo
Get some friends together and do a photo scavenger hunt
Pack a picnic and head to the park