Well, most predicament play is more about mental flexibility than intellegence per se.

A simple one, that is more about flexibility, is to have her count out her spanking. Do one cheek counted ordinally, one counted cardinally, and don't merely alternate. Each cheek must be tracked separately and spoken properly. Intermix an orgasm or two and continuing the count will almost invariable mess her up.

For an intellengence task, make her beat you at Scrabble but limit her to only using kinky/sexual words.

Edit: or incorporate this ordinal/cardinal idea into Jennifer's taskings.