If you're interested in reading web-based articles offline, you'll soon hate Adobe Reader. It's practically a platform with web-crap built in, takes too long to load, doesn't support right-left scrolling via keyboard and spams you with /home/user/RSS. Toss it.
Not too hard, then “sudo apt-get install evince” and you'll end up with:
http://xnv4.xandros.com etch/main libdjvulibre15 3.5.17-3 [773kB] http://xnv4.xandros.com etch/main libkpathsea4 3.0-30 [81.1kB] http://xnv4.xandros.com etch/main libnautilus-extension1 2.14.3-11+b1 [83.4kB] http://xnv4.xandros.com etch/main libpoppler0c2-glib 0.4.5-5.1 [40.5kB] http://xnv4.xandros.com etch/main evince 0.4.0-5 [817kB]
(note: KDE fans should probably point out another option)
Next, “sudo apt-get install evince” and you're almost there.
[Apparently] Evince isn't included in the applications list, so when you right-click a PDF for the first time, you need to “open with” then select “other” and manually type in “evince”.
Now you have a nice trim app for quicly reading PDFs, it's easily made minimal and supports right-left scrolling and is a joy to work with.
Once all is said and done, you can quickly “print” documents to /home/user/PDF (editable via /etc/cups/cups-pdf.conf) and your downtime will not be wasted.