We briefly review experimental and theoretical results related to the probl
em of long range magnetic order in geometrically frustrated 2-dimensional q
uantum antiferromagnets. We show that 2-dimensional He-3 at low coverage is
a good candidate as a Spin-Liquid. We underline that sophisticated numeric
al studies of the spectra of such systems point at least to two different k
inds of Spin-Liquids.