A Thermos Flask
A blonde and a brunette are taking a break.
The brunette pulls out a thermos and starts to sip coffee while eating her lunch. The blonde asks what’s up with the funny looking flask. “It’s a thermos flask, it keeps hot beverages hot, and cold beverages cold!” the blonde is enthused, and decides right away to get one herself.
The next day the blonde walks in the breakroom with a brand new thermos and shows it to the brunette. “Oh,” the brunette remarks, “What do you have in there?”
“Two coffee and an ice cream!”