How do I use ffmpeg's "-vf" / "-vfilters" option without recompiling ffmpeg myself?

You are right, the ffmpeg packages in Ubuntu 10.04 and 10.10 do not support video filters. If you use Ubuntu 10.10, you can add unofficial packages from the Debian Multimedia Project and install their ffmpeg version (you should not do this if you use Ubuntu 10.04, there are too many conflicts with older packages. Also do not combine those packages with ubuntu-restriced-extras). Then the following works

ffmpeg -i in.avi -vf vflip out.avi

An easier option ̣- if all you want to do is flip videos - is to use the mencoder package instead of ffmpeg. After installing the package, the following works (copying the audio, encoding the video with libavcodecs):

mencoder -vf flip -o out.avi -oac copy -ovc lavc in.avi

If you don't want to compile it yourself, you should just grab a static build from the ffmpeg Downloads page (scroll down to 'FFmpeg Linux Builds').