Galen's wooden acting when controlling his homunculus in 'Racing The Night'.
"Oh look, my liver. I'd wondered where that'd got to."
Every time Gideon brings up the smell in one area of Excalibur's tram tube during 'Visitors From Down the Street'. Especially when he figures out where it is.
"The Needs of Earth" has Jerkass anthropologist Eilerson accidentally slip Captain Gideon some human/alien porn because he was too lazy to type out a report or realize he was recording over some of his Porn Stash let alone erase it first. Most fans of the series will give a Fascinating Eyebrow at the names alone - "Snow White and the Seven Narns", "Who's Your Little Pak'Ma'Ra"... but the really kinky part must be looked up; Pak'Ma'Ra have truly Bizarre Sexual Dimorphism: half of the species is actually immobile and permanently attaches itself to the humanoid's back. A Pak'Ma'Ra's "sex" organs would be at the base of its neck. The ship's doctor mentions that this makes the entire concept absurd; cue the Head Tilt. Gideon fiddles with the data crystal in front of Eilerson just to screw with him for much of the episode, and the final payoff involves using it to distract some prison guards during a daring rescue. Perhaps too well, as even the thief was distracted to the point of head-tilt!