I reckon 'poo' is making a comeback. Simple, sounds funny and crude - does the job perfectly.
As with everything I do, I'm going to tell you the story behind this. Last night at work, I went to the toilet and it smelt quite odd - not unusual for a lavatory, I know; but the smell was not your usual crop of festering faeces and that dank urine odour - it was Chinese food. Now I'm really starting to question Chinese food... or maybe it was just because there's a Chinese restaurant downstairs. Who knows? All I know is that I started thinking about the word 'poo' and began laughing hysterically.
I also opine that 'gherkin' is a funny word.