(Think Fun $29.95) Our testers loved this latest brainteaser from ThinkFun where you are challenged to build a working rollercoaster to get the little red car from the starting point to the finish. A hands-on engineering experience that makes for a great parent-child game. Each challenge card tells you which pieces you'll need to complete the task -- and as with all ThinkFun games -- the challenges go from easy to hard. Our game testers breezed through the easy cards but then