Hot answers tagged luggage
If you are lucky/careful with your combination of sunglasses and helmet, you can store them quite securely in helmet's vents, which makes it easy to put them on/off with a single hand: (quite hard to find a decent picture of this, screen-capture is from the Vuelta a España 2013, stage 14)
At the beginning of this video: http://vimeo.com/41982043 it looks like this bike messenger has an extra strap for his bag that comes up under his left arm to stabilize his load. Looks pretty neat, like it can be easily unsnapped to get the normal messenger bag access, and possibly be DIY-able.
If the image above is correct, the frame-bag is great if all you're carrying is a credit card and a puncture repair kit. It's light, cheap, unobtrusive and doesn't add much air resistance. But if you're carrying even a rain jacket, it'll be hard to find a frame bag big enough. The frame-bag is not waterproof either, so it would be best not to carry a phone ...
I'd have a look at http://store.velo-orange.com/index.php/accessories/racks-decaleurs.html A "decaleur" is a removable handlebar bag mount. You'll still need a (non-removeable) rack for support too though, but for a retro look and larger bag capacity than without a rack, it's a possibility.
Instead of adding an additional stabilizing strap as suggested by @obelia, you could wear the bag like a fanny pack, around your waist. I'm a big fan of this solution, and I proudly sport my fanny pack (or waist bag/ hip bag) on the regular. In addition to solving your over-the-shoulder-sliding dilemma, it also has the added advantages of 1) no sweaty ...
Depending on the length of the skis a "Sandwich" of skis with the frame in the middle can work, using bungees to strap them together. also if you have a rack over the rear wheel this will further support them... Wouldn't try this for my old Downhill boards. by my newer and shorter Slalom boards would do the trick.
I have attached many things to my bike. Alas I only have a few sample pictures, to help illustrate everything I have learned so far: fig1. This is a trailer I made: fig2. These are some alternate Tesco boxes: fig3. This is how I improvised with tape to attach wood and metal onto the rack: fig4. This is an improvised basket after the standard ...
Only top voted, non community-wiki answers of a minimum length are eligible