Just got an email from the Hilton Guam, they have a special on over Mother's Day, which is the cheapest rates i've seen for this property in a long time:

US $100 per night, per room, INCLUDING TAX - single or double occupancy. Extra bed, US$30 (doesn't say if one off or per additional night).

Only valid between May 9 - May 12.

For reservations, call the Hilton Guam directly on (whatever the prefix codes for Guam are) plus 646-7912.