Much more useful than metronome tracks would be a metronome app; if you have an iPod touch or iPhone (or Android) I highly recommend Tempo by Frozen Ape software as it has a noticeably more accurate timing engine than many competitors.
When riding the bus to school you have free movement of all four of your limbs, so there's really quite a lot you could do just tapping different drumset beats in place. Even with just two hands you have mountains of material and technique to work through just on the 40 Essential Snare Drum Rudiments.
If you have a decent teacher they'll introduce you to this soon enough, but the most common useful system (ignoring non-contextualized syllables like Kodaly) of verbalizing rhythms is based on subdividing the beat into sixteenth notes in the following manner:
4/4 time:
1 2 3 4 (four quarter notes)
1 + 2 + 3 + 4 + (eighth notes, pronounced "and")
1 e + a 2 e + a 3 e + a 4 e + a (sixteenth notes. Alone, the 'a' is verbalized as 'da'.)
Instrumental students will often practice clapping and counting rhythms using these syllables, using one foot to tap the beats, the hands to clap the rhythm, and the syllables to process the notation and contextualize everything at the right time (if they're doing it correctly). For example, the opening strain of "The Stars and Stripes Forever" would be vocalized thusly:
1 2 - da 3 + (4) + 1 + 2 + 3...
(parentheses used to indicate a non-clapped beat)
Every rhythm is contextualized because a number is always used to indicate something on the beat, the 'and' always indicates an upbeat or syncopation, the 'a' indicates the second sixteenth in a beat, and the 'da' indicates the last sixteenth in a bar.
Compound meter can even be counted in a variation on these syllables, using 'ta' and 'ma' to indicate the second and last triple subdivisions, respectively, occurring after a numbered beat--see also triplets and asymmetric meter:
6/8 time:
1 ta ma 2 ta ma
4/4 with a triplet on beat 3 (increasing subdivisions):
1 2 + 3 ta ma 4 e + a
7/8 time, 3 + 2 + 2 subdivision
1 ta ma 2 + 3 +
In the last example, 7/8 indicates the pulse is constant on the eighth notes, so all syllables written happen at a constant interval.