Not this weekend but the one before me and Fiona went to Cat Ba for the weekend. It was the first time I had been there and really enjoyed it. The weather was reasonable, the Sunset hotel where we stayed was good and only $6 a night for front room and only $4 a night for back room (which we had to take because the hotel was full the first night). The journey there by bus costs 120,000 Dong (8 or 9 dollars) and leaves from the South West (I think) Bus Station at 7.15 and 11.15 which are odd times but the only times. It takes about 4ish hours and includes several buses and a boat.
We rented a very uncomfortable tandem for an hour or two and had a couple of hours rowing round a very nice bay in a kayak. The food was good and the people friendly, so overall a good weekend. We also met up with Sara and her friend which was nice.