This has the guaranteed correct distribution ('correct' being 'uniform'), too!
EDIT: I guess, to be more clear about the algorithm: flip 8 coins and convert this result to binary. If the result is greater than 240, flip the eight coins again. The number of total 8-coin-flips that need to be done on average is something like 1.062, and the likelihood that you need to perform n 8-coin-flips to receive a result ≤ 240 vanishes exponentially as (15/256)^(-n).
EDIT: I screwed up again, 24d10 is 24 dice with 10 values. Oops. Point is still roughly the same!