The Party: Your boss invites her "inner circle" of trusted employees to her apartment for a holiday get-together
What to Bring: Nice bottle of wine, or a big bomber or two of craft beer
Why: Unless you hate the idea of a sustainable career, you don't want to show up with a plastic handle of Old Crow yelling, "Where the party at!?!" This is an excellent opportunity to bond with co-workers, but don't let the fact that they're CO-WORKERS escape you. A nice bottle of wine, or a 22oz or two of classy craft beer, will trick them into thinking you don't eat cereal out of Solo cups on a daily basis.
The Party: A friend is taking you as their guest to a sporting event, concert, or matinee performance of Tony Award-winning musical Kinky Boots
What to Do: Offer to buy a beer and a hot dog
Why: Shame on you if you don't offer to at least spring for a drink and a dog. Even if they didn't actually pay for the tickets, they still took you of all people. Don't make them regret their decision or you could be taken off their extra-tickets invite list forever, which World Book confirms is a long time.
The Party: A housewarming party for a friend who, yeah, he's your "friend", but you're not calling him up to hang just the two of you or anything
What to Bring: Split a liter bottle of liquor with two buds
Why: Housewarmings are one of those events where you really look like a cheap schmuck if you show up empty-handed. That being said, you don't need to break the bank on this one considering you're not that close with the host. Get one or two of your pals who are also peripherally friends with this dude to get down on a bottle with you, and you can present it to him as a group. Make sure you're the one carrying it into the party though, so you get all the credit.