no, i'm not kidding. it has proven to be extremely valuable and useful many times. just consider this: what's the main purpose of an abacus? keeping count of things. and that's what i'm using it for: usually to keep count of sets or rounds during a workout session (am i the only one that becomes quite oblivious under extreme fatigue?), but it has proven to be even more useful for the day-long or week-long fitness goals like doing as many sets of a single exercise during the whole day (ever tried it? for me it's the best way to improve your max reps, check this blog entry for more on the subject).
maybe i'm getting old and my mind is a bit screwed up, but lately i'm quite obsessed with writing things down. i have the feeling that the fact that I don't need to keep them in mind allows me to free mindspace for something else (be it just keeping my monkey mind free to wander) so having this little abacus to keep count of the number of rounds done during the day helps a lot.
i know that there are many apps, sportwatches and electronic gizmos that do the same, but if you are trying to live a no-tech life (like i do), an abacus is the way to go: it doesn't crash and it does not run out of battery.
and i paid it less than 4 euros!