The show is about a catering team made up of 6 people played by Ken Marino, Adam Scott, Lizzie Kaplan, Ryan Hansen, Martin Starr, and Jane Lynch (who later went on to Glee and was replaced by Megan Mullally). These characters are aspiring musicians, actors, writers, and one who wants to own a soup restaurant. All of them want to make it big, but are stuck at the bottom serving people who are richer and more successful them (and also obnoxious). They work multiple events, such as a wake, weddings, sweet sixteens, and Steve Guttenberg's birthday (which is probably the best episode).
The show is not always laugh out loud funny like "It's Always Sunny" or "How I Met Your Mother," but the humor lies in the realism of the dialogue. I really recommend it to anyone who likes the actors I listed (especially Jane Lynch and Martin Starr who probably do their best work here).
The show has great guest stars, including Joe Lo Trugglio, J.K. Simmons, George Takei, and Steve Guttenberg.
Aesthetically, the show is like Arrested Development, with hand held cameras, not always going for super close ups.
Thematically it's about failure and how sometimes not all of us can be successful in life. This theme plays out through all twenty episodes, leading to a very subtlety poignant final scene.
Here's one of my favorite clips showcasing Martin Starr's Roman and Jane Lynch's Constance.