In the 1990s Hans van Klinkens Klinkhamer was infamous all over Europe, and for a good reason, It's an excellent fly that I have fished a lot myself (and still do). It has en equally effective, but not quite as infamous (although far from unknow) sinking counterpart that Hans van Klinken calls "The LeadHead". It's so named because Hans ties his fly with a lead split shot in a loop of mono on top of the hook shank, to make the hook ride hook-point-up.
We had a lot of fun discussing the virtues of this fly on the Board a long time ago, but my stand point remains that it's a very good fly.
It imitates a cased caddis larvae. I don't use the split-shot-in-mono-loop-method. I just stick on a tungsten bead, and if I need more weight, I tie and length or two of flexible tungsten sheet underneath the hook. I don't tie mine overly heavy - I like to be able to cast them on my standard trout/grayling outfit which is a 4-wt.
At the tail end of the season these heavy(ier) searching fliers become more and more important for me, and teh LeadHead is one of a trio of standards that I always tie on to begin with. The other two are teh Green Flashback Nymph (I've written about that too, but a long time ago, maybe I should re-visit it if I can't find the page) and then a gammarus imitation. If these fail, I do something else - like go home, maybe :-).
Have a great weekend!