She may be 40 (?!?) but Sarah Silverman still acts like a 20-year-old at times.

The actress was leaving the Arclight Cinemas in Hollywood Sunday night where she talked about a recent trip to Boston in which she smoked some pot, went to some party and claimed she was still in college ... and some other crazy stuff she got into while visiting Bean Town!

Amazingly, with a face (and maturity) like that we'd have kind of believed it!