A few of the many ways to generate numbers in Max

MIDI data from an external source:
notein, bendin, ctlin, etc.

computer keyboard:
key, keyup

mouse:
mousestate, jit.pwindow

onscreen sliders and dials:
dial, hslider, vslider, kslider, pictctl, etc.

timed processes:
tempo, metro, clocker, line, etc.

MSP input audio amplitude:
adc~, ezadc~

MSP signal generators:
cycle~, phasor~, line~, noise~, etc.

randomness:
random, drunk

mathematical expression:
expr

video:
jit.matrix (getcell), jit.iter