you can make something like a giveaway game. Make for example 100 boxes. Hide prizes inside boxes and when I click the box, box opens and prize is shown. and if I won I get the prize. you can make like 0.001 bitcoin prize. 10 or 20 or 30 wining boxes depend how much you want to give away. or you can use some other altcoins for a prize like dogecoin for example.
This is actually a good idea, I will ask my developer how long it would take to code.
PS. Still open for another ideas.i also like this it would be interesting to see it hapenning, here is another idea
make a referral contest,, who ever gets the most referrals in amount of time, that user or users get prizes in bitcoin?