Check out the #casine. It's basically this. Each block hash ends in a hexadecimal. You place a bet 0-F what the last digit will be. 16 possibilities. You can scale this by betting last two digits instead.

nostr:npub12r0yjt8723ey2r035qtklhmdj90f0j6an7xnan8005jl7z5gw80qat9qrx nostr:npub1ymt2j3n8tesrlr0yhaheem6yyqmmwrr7actslurw6annls6vnrcslapxnz nostr:npub12gu8c6uee3p243gez6cgk76362admlqe72aq3kp2fppjsjwmm7eqj9fle6 nostr:npub1r8u6lw8c2h67s66magtqu78vtpckfzcsmmdsg06gqm723njsunfs8kfjwl