I stumble yesterday upon a funny, not complex little game that resemble pretty much mine sweeper. 
It is a flash animation, so this has nothing to do with free software. But it is just fun to play. It is much like mine sweeper but with numbers. A number indicates how much golden tile there are adjacent to it. This make it pretty simple when the number is 0 or 4, or even 3 next to a border or 2 at a corner.
Easy but fun . 
Ideal to relax 2 minutes.