How about you send me a Saber sometime this week and people guess what day/time it's delivered to my home?
Personally I like contests that give me a good chance. Random.org hates me, but if I can spend the time to enter multiple times I WILL put in the time, someday random.org will HAVE to let me win right! I don't do video contests (and other people don't either, so if you go that way there will be less people who enter - maybe not a bad thing but just pointing it out). I like photoshop contests but not everyone can/will enter those. Quiz/knowledge contests are not fair because I'm dumb.
Whatever you decide will be fine as contests are ALWAYS welcome! (and if it could be done in such a way as to ensure my win, so much the better!)