There are tons of examples of Government being funny. But, I agree with everyone else, being funny on the main IRS page when people are having a hard time paying their tax bills is not funny, but at another time of year, they could get away with being funny. Just be careful of how other's would see it. Funny to us, may not seem so funny to the general audience.
I will give you one last thought on funny; Old Spice is about as not funny as you can imagine. Come on my father wore Old Spice and all their commercials were always about serious goodlooking men doing serious stuff. Nice to look at, but what woman really wants to be with someone who is serious 100% of the time.
Now look at their commercials - every women in our building is laughing everytime the commercials come on. They are so incredibly silly, but still great! Oh my gosh, I am laughing just thinking about the new commercials. So, yes, we can change from 100% serious all the time (like our father's Government), to wearing the new Old Spice! We can be funny and get the job done! 🙂