There's one in Tracktion 3. A lot of users were complaining that there wasn't a more traditional mixer in Tractkion, and there still isn't in Tracktion 3. When you look through the assignable keycommands there is one there to Show Mixer.
Assigning a key and pressing it just brings up a picture of a Mackie mixer that doesn't do anything.
In BFD 1.5, when you're in drummer's perspective mode... after the GUI's been open for long enough, there are some hilarious conversation text balloons that come up from the shadowy figures on the other side of the glass window, in the control room.
In Adobe's Audition, you go to the about section, click on the "o"'s, and they drop down like little marbles, then after a few second you can click on them again to get more marbles bouncing around.... you can get lots of marbles bouncing around.