Your cup of tea is anything that you like or enjoy doing. It can be a characteristic or a quality; it can be an activity, a thing or someone's personality. Usually, this phrase is used in the negative. So you usually say that something is not your cup of tea, and you say this to express that you simply don't like it and usually for no other reason.
So if someone invites you to go bowling, and you turn down the invitation simply because you don't like going bowling, you can say, "I'm sorry. Bowling is just not my cup of tea." You can say this about anything you don't like. Perhaps a particular food is not your cup of tea, or skinny dipping or people being loud in public or amusement parks may not be your cup of tea. Anything that you'd rather not partake in can be described as not being your cup of tea.
A: I'm so excited about the trip to the Grand Canyon next month.
B: I'm not. I love the Grand Canyon, but I just don't like hiking.
A: Oh, I'm especially looking forward to that.
B: Not me. Walking for hours in the hot sun is just not my cup of tea.
A: I think we're going to start walking in the early morning, so it shouldn't be too hot.
B: I hope so. I'm not too much of an outdoorsy person, but I am looking forward to partying in Vegas.
A: Not me. I'm sure I'll enjoy walking down the Strip, but drinking and gambling are definitely not my cup of tea.
B: Well, at least there's something for everyone on this trip.
A: That's for sure.
bowling - a fun activity where you roll a heavy ball down a lane to knock down some pins
turn down - say no to an invitation or a proposal
skinny dipping - going into a pool or the ocean completely naked
partake in - participate in; have; use
outdoorsy - (slang) someone who enjoys being outdoors and doing outdoor activities
that's for sure - I completely agree.
Alright everyone, try to use this phrase in the next few days. There should be plenty of opportunity to do so.