Education in Futility: WarpWallet Brute Forcing
So the makers of it had challenges setup. By the time I stumbled on it, only the last challenge was left, with 6 months remaining. For that challenge, the reward for cracking an 8-character alphanumeric password was 20 BTC (and BCH and BTG!), which was worth over $100,000 USD at the time of the challenge end date.