I decided to check Merriman-Webster online. Now, their definitions did seem brief (to say the least), but it seems that neither 'essay' nor 'assay' are appropriate...at least according to these definitions and the intent of the original poster. 'Essay' means a tepid beginning or attempt. This strikes me as having a prejorative connotation that I do not believe TEACHEROFTHEATER intended (although, of course, I could be wrong).
I, myself, have used these words carelessly, and now, thanks to the debate, I will be far choosier in my word selection. I will stick with the word 'perform' or 'performing', though it doesn't quite as lovely. I love learning new things!
"I'm so looking forward to a time when all the Reagan Democrats are dead."