As mentioned earlier, know your crowd. With some I can say with a grin  “What did you expect what you booked me to call on April 1?” and we can all have a good time. With others, not so much, so use “Fool-ish” dances sparingly.

Some of my usual, easy enough for most crowds, Foolish tricks, include:

Left hand chain: Any dance with a full chain (e.g Summer Sunshine), alternate full left hand chain (formerly Gent’s chain, from the usual side), with the standard full right hand chain.) I’ll often use this early if I have a left hand chain later in the program, teaching the LH chain first, demo-ing if necessary.

Swing the wrong wayMorning Star or here (Actives Balance Swing CW as usual, then Bal and Swing CCW, “Ideally with the 'other hands joined’ in waltz position, with the left foot in front for the buzz step --- or some other way you can work it out!”) Amazing how hard it is for even many experienced dancers - think about how new dancers must feel! Can alternate 1s 2s as the actives, and dance proper or not.

What, no progression? Teach (1 or no walkthrough) and call a Becket A1 Slide left and Circle L dance without the slide left the first 2 or 3 times through…”same 4, circle left 3/4…” before, as some dancers catch on and start to murmur, “April Fools! This time,  slide left and circle…”

An Alternating Dance, esp Sun Dance and Moon Dance. Robert Cromartie. Alternates A2 Larks BS in middle with A2 Robins BS in middle, with some alternating tweaks to A1 and B2 to make it work. Or other two similar dances, maybe 1 version 4X, then spring the other version 4X then 2/2, then 1/1 e.g Hey Man, or a Jed’s Reel/Edna’s Reel medley 

A real dance (not much foolish except for the A2 which give those that only dance that lefthand/Larks/Gents role a chance to experience the lovely chain to hey combination): 
Chain of Fools, Steve Pike
A1 BSN
A2 Left hand chain to P, 1/2 hey (those who chained - Larks - pass left shoulder to start, NR, they pass L in middle)
B1 P BS (or RSR/Swing)
B2 Cir L 3/4, PT, next N DsD ( alt: Cir L 3/4, Bal, PT…)

Steve Pike
Mequon, WI