if you go in the menu section of an ipod then extras then games those are clickwheel games they are included with every ipod
No idea why those would be "clickwheel" games. Those are games. Since the Ipod only has a clickwheel that's the input hardware to control them, but apart from that there's nothing tying them to the input method. Solitaire on my PC also doesn't depend on the input method ...
Rockbox is a complete replacement firmware. It does not run Apple's firmware, thus all stuff Apple provides with their firmware is not relevant to Rockbox. Rockbox does have a couple of games, as saratoga mentioned. You control those with the input method your player provides. In case of an Ipod it would be the clickwheel, on other players it's buttons or the like. See the manual for the games Rockbox has. The available games also depend on your player -- not all games run on all players.