I need some help!!

We are going to one of DHs coworkers tomorrow for dinner. I offered to bring dessert. His coworkers wife is an AMAZING cook. She made us a couple meals right after we had our babe, and her stuff was great (she brought homemade soup, salad, bread and a nice chicken dinner!)

What can I bring for dessert that I won't royally screw up? To show you how good my cooking skills are --- dinner tonight is canned soup and bagels! AH! They have a 5 year old, 3 year old and 1 year old. Any suggestions are much appreciated!