I'm guessing v372 for Ubuntu probably works on Debian, since they're largely similar. If it doesn't, I've been running v360 on squeeze and haven't noticed any issues with arc3. Failing either of these, you could build v372 yourself.
Once MzScheme is installed, there's not much to do about Arc that's not already on http://www.arclanguage.org/install. You might consider aliasing it in your .bashrc (or whatever), and I recommend using rlwrap. e.g.,
alias arc='cd ~/arc3; rlwrap mzscheme -m -f as.scm'
I would add (for other potential readers) that it is a very neat self-installer that makes it possible to install in user directory (so that it doesn't spread on the whole system).
What's more, this i386 version worked smoothly despite my amd64 kernel.
Right, the username. Someone who figured out I was French (a space slipped before a question mark) on a lisp-related IRC chan told me there were many French Lispers. I wonder how many we actually are.
In Paris too, and I'd be glad to meet some other lispers. Especially since I'm still in the early process of learning Lisp. But I guess we should find another way of dealing with IRL meetings than the forum...
Great! Thank you so much, I indeed missed the link on PLT's download page. I'll try it as soon as I'm back home (I can't wait). And thanks for the rlwrap tip too!