You could always help her with the decorating. Agreed - spa holidays (unlike Spa holidays, which are great) sound like the absolute pits to me. A weekend with the o/h in Paris would be better! But then, if it were me, you wouldn't be allowed to Silverstone without taking me along. Whatever, for myself, any hol' I didn't have to do all the organising for would be nice... and unheard of!
Thought : Why not ask
her what she'd like to do?
Edit : Mr T's advice "buy her a bigger paint brush".