Not actually special, but I use this one usually, to drink large quantities of this - it's absolutely the best Earl Grey I've tried, out of Celestial Seasonings, Taylors of Harrogate, Twinings, and others, well worth the price (I subscribe to it, so I save 15% too, and you can get probably 40 cups from one jar). It's very heavily scented with bergamot, but the flavor is very balanced, not what you'd expect after smelling it.
I had a mug in the shape of a boob and it said "Super Sipper" on it. Sadly, it met it's fate on my kitchen floor, shattered in a million pieces. I'd find a pic of a similar one online but it may not be appropriate to post it here. I miss that thing, I never replaced it due to having a youngster running around here now.
I have one of these that's my pride and joy (not that I drink coffee in it). I bought it a couple of years ago though - before Portal 2 had even been announced - so it was a lot less mainstream then (thus making me that much cooler). I also have an Aperture Laboratories numbered parking permit, just for fun.
I don't drink coffee so I had to dig my mug off a shelf in the garage. I received it as a christmas gift along with a more interesting knickknack that I will post just because I don't collect knickknacks so it was stored right next to the mug, so at least someone will now see it.
While I usually just mainline the stuff, I do occasionally use a mug. This one is retired. My current one is plain black, very boring. The chicken mug was a present from an ex-girlfriend when she moved across the country. It came with a cactus in it. Maybe she was trying to tell me I was a prick ( actually we were still friends). It didn't take me long to kill the cactus by over-watering. After that I used it as my coffee mug for years. I finally decided to stop using it because it felt very cheap and fragile. When it was full I never held it by the handle because it felt like it would break off. Now it sits on top of my monitor.