Maybe enter people into lotteries and send out gifts to people who buy a certain amount of steem like some startups do. Maybe you could create actual physical coins with wallets on them or something like.

How about Steem scavenger hunt/ geocache? People can buy clues to each step and the prize could be physical wallets of Steem.

Sure they are all being done already, lol. So much unseen creativity on here they create so many great things.