OS X Good Mac game?

Yes. It's called Desktop.

Although Pocket Tanks is old but you can play it via mouse.

Crow is okay, too.

I think there are many other ported iOS games that do not require keyboard. Also, most adventure games.

Kings Bounty series!
Heroes of Might and Magic.
Civilization games.
FTL- Faster than light.

Also some older games over at Gog.com like fallout 1 and 2.

For nostalgic reasons, I can strongly recommend Civ IV as a mouse centred game.....you need the keyboard if you want to enter a new name (as opposed to default) at the start

Just downloaded the 'complete' set from Steam....and played it from start to finish without a single hiccup on OS X.

Just switched from a windows PC, so this was a very pleasant surprise.

There are some posts in relation to Civ V having some issues under ML so I'm steering clear until that's fixed.