Simplify the following text for a Grade 9 native English-speaking person.
Original: In Ratchet & Clank : Going Commando , Ratchet & Clank : Up Your Arsenal and Ratchet & Clank Future : A Crack in Time , the player can visit an easter egg known as the `` Insomniac Museum '' .
Simplified: They made two Ratchet & Clank games for the Playstation Portable , called Ratchet & Clank : Size Matters and Secret Agent Clank .