Decentraland, a crypto-based virtual-world gaming platform on the etherium blockchain, has recently gone live. They are currently running a four-day treasure hunt to encourage users to sign up. To own land or claim an avatar name, one has to spend some crypto. Signup/exploration is free.
https://decentraland.org/blog/announcements/decentraland-treasure-hunt/
https://cryptobriefing.com/decentraland-has-finally-gone-live-on-ethereum/
Budget: 300TECH