I'd let him have a small splurge and toss the rest towards a goal.
For us, Un budgeted income varies on the amount but normally a splurge with the balance tossed in general or vacation savings.
Recent splurges DH bought me an iPad (over the summer) and I made him pick a snowblower since he was holding off because he didn't want to spend the money after I got sick. (this was before he figured out I had good STD and LTD coverage). The rest of the money from these two went into vacation savings for a big trip after I'm done with treatment.
His next one will probably be spent on house wants as he wants the yard regraded.
Eta: our SL interest rates are really low as is my car loan we make more with it in savings or investments.