Throw firewood 

An action that describes a made-up prior engagement in order to dodge duties, plans, or other activities solely because you really didn't want to, but wanted to spare feelings. Made popular in Skyrim where some quest givers may ask of you a menial task and you respond with an equally menial task in order to exit conversation so you can come back and get it later if wanted.

You: "Hey, want to go bowling?"
Person: " I cannot as I have to Throw firewood later."

Throw firewood by Yodamane January 1, 2012