I'm almost afraid to write about TimePlus because it is such an accurate simulation of the LCARS interface from Star Trek: The Next Generation (complete with sound effects) I worry that the lawyers will descend upon the developer and force him to remove all traces of familiarity in the app.
Still, TimePlus is too fun not to write about. If you're a Star Trek nerd like me, TimePlus gives you not just a big clock as you see above, but also timers, a stopwatch, two alarms and a world clock. Plus, you can use it as a sort of screensaver, or reduce it to a "nano" clock, or access world times in your menu bar. All of this is super handy if you manage people around the world (as I do), or use time management like the Pomodoro technique, or just want to geek out with something Trek-y in your daily life.
TimePlus is free on the Mac App Store, although you may need to install the LCARS font first to get it looking just right. There's an iPad app as well called Clock Tacular which costs a reasonable $.99. If you want a fun clock on your Mac, download TimePlus and make it so Number One!