I bought food, ma!
I rented some movies, ma!
I went to the movies, ma!
I played some pool, ma!
I went rollerskating at the roller rink, ma!
I went bowling, ma! (If you use this excuse, it'd be like you didn't lie)
I soiled myself and bought myself some new underwear, ma!
I needed Preparation H, ma!
I like phone sex, ma! (This will definitely make your mom talk... maybe say this one just for the reaction)
Okay... I'm suggested out.