To get people excited about cube, I draw comparisons between it and Masters sets, or talk about it being like the MTGO cubes without the broken stuff (that said, it's important to not actually
list what broken stuff you're leaving out so that people can pick and choose what broken stuff they hate [Power? Storm? Aggro???] and assume that you don't have that).
For me, the big draw of cube is that a lot of older Limited sets were kind of frumpy. Cards are better nowadays, but you still get things like
Sugar Rush, which just aren't that exciting. I'd appeal to the "what if draft, but better?" mentality first and foremost.
Alternatively, grab a singular friend and play a grid draft or something. It takes up a lot of space and looks funky, and it's a great way to show off the cool cards in your cube. People will likely start asking questions, opening the door for you to Tom Sawyer them into liking the cube.
Prizes could also be the ability to sign a basic from your basics box, if you're into that, or giving them a common from their deck/a card under $1/the MVP card from their deck with the stipulation that it's something within reason, i.e. not your ABUR duals. If your cube is cheap enough, a singular card could be a lot cheaper than a set of six packs or what have you, even if it *feels* worse.