Depending on how familiar I am with the sound tech, I like to vary between the standard "check 1-2, testing testing. The quick brown fox jumps over the lazy dog. Spinx of black quartz, judge my vow. Richard of York gave battle in vain." to "this is your mic checker, checking in. It's a balmy room temperature in here, uhhhhhhhhh...." and then talk like a airline pilot giving the pre-flight speech. Or even start making basically every audible sound I can think of that they might be dealing with while also trying to make the tech laugh because I know he's usually super serious and doesn't get anything other than the usual "check one two three" 9/10 times.