I was watching the Macabeats D'ror Yikra where they use cups as instruments to keep the beat and enhance the way the song sounds. Obviously this was not filmed on Shabbos (Duh!) but I was curious if there were any aspects of the way they sing the song and keep time and enhance the sound with their hands and cups that would be forbidden to do on Shabbos.
The Mishna in Beitza 5:2 teaches that one may not clap their hands or slap their thigh, lest they come to make or fix instruments (Rashi to Beitza 36a - keeping the beat this way will lead to simcha and song [which will lead to music and instruments]).
ולא מספקין, ולא מרקדין, ולא מטפחין.
The Shulchan Aruch O.C. 339:3 extends this to banging with nuts, meaning even beyond musical instruments.
The Rama there cites Tos. in Beitza 30a who says that today we don't know how to fix instruments, so the concern does not apply. The Mishna Berura 339:10 says not to rely on this.
Rabbi Daniel Mann discusses this question and concludes that it is better not to use cups as instruments, however there are are those that would permit it.
Back to your cups. Cups are not a musical instrument. Are cups on a table worse than hands on a table, considering that, either way, the table is a makeshift drum? (Unlike most drums, a bongo drum is played by hands on an instrument). They might be slightly worse, as hands hitting many things, including each other, produce noise, so hands on a table may be compared to clapping, while cups on a table more closely resemble a makeshift musical instrument (see Shulchan Aruch, OC 339:3). Importantly, the lenient practice is regarding hands, not instruments, on the table (Bnei Banim I:12). However, since some rabbis would permit the cups and most rabbis do not protest when people do something similar (i.e., banging with hands), any step you might take to avoid confusion is, perhaps laudable, but not mandated.