China Garden in Irvine, CA serves Dim Sum and dinner and is open everyday with long hours including major holidays. For Orange County where there aren't that many Chinese residents as it seems, the food here is pleasantly delightful with good customer service. Just beware that the wait for a table can be long and parking can be a bit of a hassle.
I have been going to Dim Sum since I was five years old...unfortunately, I don't know the English names to most of the items and my friends who were with me didn't know the names either.
A few Dim Sum items:
Dim sum is a Cantonese term for a type of Chinese dish that involves small individual portions of food, usually served in a small steamer basket or on a small plate. Going for dim sum is usually known in Cantonese as going to "drink tea" (yum cha, 飲茶).
Dim Sum is usually linked with the older tradition of yum cha (tea tasting), which has its roots in travellers on the ancient Silk Road needing a place to rest. Thus teahouses were established along the roadside. Rural farmers, exhausted after working hard in the fields, would also go to teahouses for a relaxing afternoon of tea. At first, it was considered inappropriate to combine tea with food, because people believed it would lead to excessive weight gain. People later discovered that tea can aid in digestion, so teahouse owners began adding various snacks.