Once in Brugge or Ostende you can buy a day travel pass for about 5 Euro for all buses and the tram that goes from the French border to the Dutch Border, well worth it. It will also take you from Brugge to the coast. Be corny if in Brugge and ahave Mussels and Frites in one of the cafes on the main square it's a cliche but real nice. Then walk the missus round all the chocolate shops that give free tasting before you buy some. Canal trip is crap mind you, pleasant enough just boring.
Could always go on the Harwich-Hamburg ferry. 24hr crossing, with a casino and plenty of bars and enterntainment on the boat. Then it drops you off close to the old historical part of Hamburg, with everything in walking distance ... including the Reeperbahn!!!!!!!
Funnily enough, I'm just back from a 72 hour extravaganza minicruise thingy. P&O does a three day round trip between Portsmouth and Bilbao (Northern Spain), right across the Bay of Biscay. It was great - dolphins doing acrobatics alongside the boat, there's decent shops on board, entertainment in the bar each night, decent (but expensive) scran and it only cost us £65 each. We (me and the missus) had a little twin ensuite (bog + shower) cabin which was a bit wee but it did the trick. You just turn up as foot passengers and go along for the ride. At the far side you only have 4 or 5 hours in Spain but it's long enough to stock up on fags'n'booze. Check out http://www.poferries.com/tourist/co...th_-_bilbao_onboard_-_portsmouth_-_bilbao.htm for more details. I thought it was great.