737 Taipei to Guam. Tropical typhoon forecast to be on our track about 600 miles from Taipei. Night flight very dark. Radar scanning ahead for first signs of storms surrounding the eye of the typhoon. Passengers sleeping peacefully, no drunks thank goodness. In cloud but radar has slight ground returns from big waves (or so we thought) but still no sign of storm clouds. Figured typhoon must be well off track. Then without warning straight into severe turbulence, lightning, St Elmo's fire on the windscreen.
Thinks WTF! Check radar tilt and Gain control. Switch distance scale. Radar still peaceful scene with apparent slight returns from sea below. More very heavy turbulence. Turns out radar must have failed earlier in cruise but no warning. We had hit the first storms surrounding the eye. Took a punt and turned 90 degrees right and spent next ten minutes with both pilots heads peering through windscreen watching for gaps and weaving between storm tops that were illuminated by lightning flashes.
Eventually left storms behind and turned to track to Guam. Pacific island air hostess came up front with coffee and said "that was good fun, can we have some more bumps, please?". "You're kidding" said the F/O "why do you want more bumps?" "Because we can have a sleep and don't have to serve dinner to the passengers" said the girl.