best of vienna in 1 day

First, you should know that Aug. 15 is a public holiday in Austria. Shops will be closed (including grocery stores), but restaurants and attractions will be open. Public transport will run on a holiday schedule. You probably won't notice the holiday too much, but it will be quieter as many locals will be away.

The best way to get to Salzburg is by train - and you have two options. OeBB and Westbahn both offer high speed train service from Vienna to Salzburg. The journey takes 2.5 hours. OeBB tickets can be purchased in advance, online for a specific train for 19 Euro. OeBB tickets purchased on the day of travel will be at least double that price. I would recommend Westbahn as you simply walk on the train (there is one every hour) and buy your ticket from the staff onboard. The ticket price is 23.50 Euro. Westbahn trains leave from Westbahnhof as do OeBB trains.

Now as for what to do in Vienna...please first describe your interests. Museums, walking around, churches, markets????

Here's Rick's online page for Vienna. If you click "At A Glance," you'll see his suggested highlights (remember, these are only his opinion): http://www.ricksteves.com/europe/austria/vienna

I say go kick it in Museumsquartier. Have a beer. Chill out. Maybe venture to one of the big museums across the street. Stroll Mariahilferstraße a bit if you feel like it. Cross into the First District and walk to Stephansplatz. Check out Graben, then head to the 4th, 5th, 6th, 7th or 8th for dinner (your teenagers will probably prefer that to the inner city). I'd recommend zweitbester, 25hour hotel's burger de ville, maybe a place on Florianigasse.

A lot of stuff I would normally recommend will definitely be closed (it's a holiday).

Holiday or not, take a strassenbahn (tram) and ride completely around the Ringstrasse. Get off where you first got on, then walk to the city center and go inside Stephansdom (watch your wallets and purses when inside!). Then, walk down the Graben, and on though the Michaelerdom to the Hofburg Palace complex and the Heldenplatz. The twin museums (Art and Natural History), with the Maria Theresa stature in between them, are across the Ringstrasse from the Hofburg Outer Gate, but I would suggest skipping them. For lunch, have a schnitzel somewhere in the old town (1st district) while sitting in an outdoor section of a restaurant and watching the world go by (there are tons of places to do this). After lunch, take the U-bahn to Schonnbrunn Palace and walk around the gardens and up to the Gloriette at the top of the hill. If you don't feel like doing that hike, stop in Europe's oldest zoo if you want (also located on the palace grounds). Take the U-bahn back to the city center and, if you're running low on energy, stop into one of Vienna's famous cafes (or any cafe konditerei that looks appealing) and have some pastry and a coffee or cola (for the teens). Have dinner at a heuriger (but not in Grinzing; suggest Schubel-Auer in Nussdorf at the end of the "D" strassenbahn). Although an abbreviated but fast-paced itinerary, I think that this will give you a great feel for this magnificent city!

Are the hotels already reserved in Vienna and Salzburg? I would certainly prefer more than one day in Vienna, especially if that is the start of your trip, when you'll be jet-lagged. Do your best to sleep on the airplane. For variety, choose either the Hofburg Palace (city center) or Schonbrunn Palace (subway ride), but probably not both. Although it certainly doesn't rate as the top art museum in Vienna, I love the quirkiness of Kunst Haus Wien and the artist Hundertwasser; that would be something to add if you weren't in a rush, and it's not far to continue from there to an evening at the Prater amusement park (open 'til midnight).