Mass Effect 3's Citadel expansion is rife with easter eggs. And when I say "rife", I really do mean that it's so full of easter eggs that you can't help but regard Citadel as anything but a love letter to the fans of the series rather than a more serious expansion to the game's canon.
In fact, much of its story is so ludicrous that if you played it, you'd realize how the expansion does not take itself seriously any more than any player who experienced it would.
Among the game's many easter eggs is an interactive cutscene in which James challenges Commander Shepard to beat his workout record. The scene prompts the player with Renegade and Paragon interrupts and lasts for close to 15 minutes if the player doesn't give up before then.
Beating James' record doesn't give you anything other than a pat on the back from James, who sends you on your way as soon as he acknowledges your persistence. It's about the biggest waste of time you could ever hope to spend in Mass Effect 3, so here's a video of someone doing just that. Watch it, in case you don't feel like spending 15 minutes of your life by doing it yourself. Feel free to skip to the end for the results.