Playing other brass instruments
I try to play all the other brass instruments. It gives me a lot of pleasure and a great learning experience. Below I will tell a bit about this "hobby" of mine. Stay tuned, I'm discovering new things all the time.
Great players
There are a lot of great players in this field, and I will mention some of those that I admire, both as players and teachers. I'll present them in an instrumental order, starting with the horn, then trombone (baritone) and below that, tuba.

One of the greatest musicians in the last century (1921 - 1958) was a british horn player, Dennis Brain.
There is a page on the Internet about him: The Legacy of Dennis Brain. Before his tragic death, he made several recordings. Some are available on CD's. Here is a Dennis Brain Discography

We have a great horn player and teacher here in Norway, Frøydis Ree Wekre. She has published a very useful and stimulating text book called: "Thoughts on playing the Horn well"

TPIN'er Christopher C. Stratton has some advice for buying a horn.

Some horn links:

A great classical player on trombone is a Swedish guy, Christian Lindberg.
In the jazz field there are a lot of great players, both in the past and present: J. J. Johson, Kai Winding and Jack Teagarden

There is a lot of info about trombone on the Internet, one place to start is at The Trombone Homepage
Another great site is that of Bass Trombonist with Boston Symphony Orchestra, Douglas Yeo
Yet another great site is:

The Euphonium also has lot of info i cyberspace like, Euphonia Rex
Hear the great Euphonium player Steven Mead "decompose" Facilita (RealAudio)

Another great musician and teacher is the tuba player, Arnold Jacobs. A book about him called Arnold Jacobs: Song and Wind gives you a lot of informations, not only about him, but also about brass playing in general.

Another player I admire, is living here in Norway. He is a member of the group Brazz Bros. His name is Stein-Erik Tafjord. He is a versatile player that is at home both in "legit", jazz, folk- and other types of music. One of the techniques he masters is "circular breathing". Watch out for him.

A "must have" book for tuba players (and maybe for other brass players) is Roger Bobo's book "Mastering the Tuba", (1993) Editions Bim.

Tuba links:

Doubling on brass
Nick Drozdoff from Chicago is a great trumpet player (with Maynard Fergusson in the early 80's) who also doubles on other brass instruments. He has made a CD with himself, playing all the brass.
At his web-site there is also an interesting article called: "Myths About Doubling" - well there is a lot of other good aticles as well !

My Warm Up routine.
I have to play on each instrument every day, and I have come up with a simple warmup routine:
Warm Up on all my horns

My brass instrument collection.
(Click on image to see a larger one)
Type Key Fabricate Mouthpiece
Trumpet Bb Bach Stradivarius Mod. 37 (Leadpipe 250) Chase Sanborn GR 66
Trumpet Bb Selmer Claude Gordon Chase Sanborn GR 66
Mini Bugle A 'Pops' McLaughlin Conn 4
Pocket trumpet Bb York Jupiter 7C
Natural trumpet Eb/D Hopf Barock type
Wooden trumpet, Lur Bb Magnar Storbækken Wood type a'la Monette
Alto horn Eb Philipp Reichel Unknown type
French horn Bb/F Meister Kurt Knoth, Markneukrichen,
detachable bell, compensating (not double)
Bach 3
Baritone Bb Besson Westminster Dennis Wick 6BS
Tuba Bb Yamaha Bach clone

O.J. - 1998