Here’s a (very! rough) Hobo cheatsheet, in PDF and HTML formats.
I’m not posting a Markdown version since it mangles source code, and is therefore only useful for natural language text.
Update: The PDF has been updated so that it’s easier to read. I accidentally put two pages of text on each page of the PDF, making it hard to read. I decided that, other than the font size, this was a good thing, so I just upped the font size and left it using a 2-page/sheet layout. Here it is.