Rules:
Player gets 3 attempts -- the highest score from the 3 attempts is the player's final score. Each attempt uses 5 dice. Only the even sides (2,4,6) count towards a player's score -- the odd sides (1,3,5) count for 0.
To start an attempt, the player rolls all 5 dice. The player must freeze one or more of the scoring dice (only even-valued dice can be frozen) -- if the player cannot freeze any dice, the attempt is fouled and scores 0. Once frozen, a die cannot be unfrozen.
The player can then stop and score the sum of the even dice, or may reroll the unfrozen dice. The player must freeze at least one new die after each reroll -- if the player cannot do so (because all the rerolled dice landed on odd numbers), then the attempt is fouled with a score of 0. The player can stop at any time and score the sum of the even dice.