Once: Win a flight to the edge of space from Adrenalin.com.au
Pretty cool prize on offer here. The winner gets to fly to Russia and then from there up to 70,000 ft in a MiG 29. You also get the flights, accomodation and a tour while in Russia.
To enter you need to give them contact details and by default sign up for their newsletter.
There is a bit of a stupidly long open time on this competition. Entries are open until 5th of Sept.