1 player. Your instrument is a series of glasses, tuned to distinct pitches by filling them with water to varying levels. Normal water glasses will work if you play them by tapping them (gently!) with metal spoons. For a more refined sound, as well as the option of eliciting long tones by moving a moistened fingertip around the edge, use delicate thinned-walled crystal glasses. Make up your own glassy music.
Suggestion 1: Do a search on Wikipedia (or other source) for the glass harmonica and read up on the history of making music with tuned glasses. Did you know that Benjamin Franklin, Marie Antoinette, and George Washington were glass harmonica players?
Suggestion 2: Locate and listen to recordings of the glass harmonica by composers such as Mozart, C.P.E. Bach, Beethoven, Donizetti, and Richard Strauss. Be inspired!
Suggestion 3: Acquire some fluency on your glass instrument, experiment with numbers, tunings, and arrangements of glasses, and then integrate the glasses into improvisation sessions with friends.