A couple of papers on the Hyperion, Saturn's large, hamburger-shaped, semi-chaotically rotating satellite has been published in Science based on results from the September 27, 2005 flyby by Cassini. The first paper, by Peter Thomas et al., discusses ISS results at this moon. The second paper, by Cruikshank et al., discusses VIMS results. Here are a few links
Nature press release
Hyperion's sponge-like appearance
Thomas, P. C. et al.
Nature 448, 50-56 (5 July 2007)
Surface composition of Hyperion
D. P. Cruikshank et al.
Nature 448, 54-56 (5 July 2007)
NASA Finds Hydrocarbons on Saturn's Moon Hyperion
Cassini Scientists Wring Out The Details On Spongy Hyperion