That's quite an accomplishment. I hear that people who get a reward check from him for errata or other help usually frame them instead of cashing them.

According to this, he has a secretary that filters messages for him: https://www-cs-faculty.stanford.edu/~knuth/email.html

Don't be too impressed, I didn't get a cheque. He's just a really nice guy.

FYI, he stopped sending checks back in 2008 due to check fraud: https://en.wikipedia.org/wiki/Knuth_reward_check. It's a shame. I had a professor that had received one for finding a bug somewhere and he proudly displayed it in his office. It was a pretty good conversation starter.

He still sends paper checks, issued by a fictitious Bank of San Serriffe, so you still have something to frame, in addition to being listed at https://www-cs-faculty.stanford.edu/~knuth/boss.html

And, at least in my case, he included a comic strip of a guy cashing a cheque at the bank, being asked by the bank teller what he got this cheque for. "Three dollars? You sure work cheap!".

I found that hilarious.

Ahh, thanks for clarifying. I knew about the fictitious bank, but didn't realize you got a paper check for it.

Lockheed's legendary Kelly Johnson was said to have given quarters to anyone at the Skunkworks who won a technical bet off of him. I believe these were also treasured by those who got them.