One Hundred Coins is simple to make and a very engaging outdoor game. The idea is that teams move from location to location around the play area while answering questions. For each correct answer, the team gets the shown amount of coins. The majority of the questions give positive coins, but some give negative. The goal for each team is to get exactly 100 coins.
Creator Pro is a block based drag&drop interface for creating rules for your games.
It is the most flexible way of creating unique game mechanics.