I didn't compile this list. I pulled them from a website back in April of this year. I wanted to share them to the Interwebs, mainly for my own future reference.
Merendar - To have a snack or to go out for an afternoon snack.
Te Quiero - Moore meaningful than "I like you," but less meaningful than "I love you."
Pena ajena / Verguenza ajena - To be embarrassed on behalf of someone else.
Estrenar - To wear or use something for the first time.
Sobremesa - When the meal is finished but the conversation is still flowing at the table.