Nepal acclimatisation

We are going to be in Nepal in December. We'd like to do the 7/8 day jeep trek to Lhasa early on in the trip but we know we need to acclimatise first. Does anyone have any suggestions as to where we could go, not too far from Kathmandu, to acclimatise (and of course do something interesting/enjoyable)?

I just replied to the same question two postings down
Hope that helps
Rob