* Basically anything to do with sheep. Whether it's an enthusiastic sheep farmer waxing poetically about his ram, or one of the historians' many attempts to handle obstinate life-stock, it tends to be pretty hilarious.
* Ruth's daughter trying out smelling salts in "Victorian Pharmacy" and describing it the smell as a filthy loo "that someone's sprayed lavender all over". (Smelling salts being made mostly of ammonia, which was historically extracted from urine.)