Of all the toys, the Micro Chargers Time Track is the one that seemed to attract the most kids regardless of gender and keep them occupied the longest (aside from putting together LEGO sets).
Pros: Although the directions were sparse, the track was relatively simple to assemble by a mom who admitted she's put together her fair share of race tracks in her day! Play was fairly simple. Just wind everything up, push a button, and the cars are off and ready. The ease of use and fact that things go fast seemed to be what attracted the kids most. They would have spent hours letting them fly around the track if we'd let them.
Cons: Even though there are four lanes to the track, the set only comes with two small cars, and I do mean SMALL. Unless you have a place to store them, be ready to have them get lost. Also frustrating? There's no way to turn these cars off!