Hettinger used tinyurl URLs in all his presentations to give short URLs to resources like CPython source code. Unfortunately I miss-typed a '3' into an 'E' and landed on a gay porn page. This wouldn't have been a problem but I was sitting in the front row and the room lights were out so my screen was BRIGHT. I couldn't just close the page because it had popups, I had to bookmark it first, etc.
The price of a con varies but costs about the same as a vacation. For EuroPython the plane ticket from Boston to Vilnius was $1400 ($600 for the airline, $800 in taxes!), conference hotel was 100 euros/night, walking-around money was $60/day. If you plan ahead (which I did not) you can save money on everything but the airfare. Some of the attendees stayed at a hostel (15 Euros/night) or rented an apartment (50 euros/night). Food and drink prices vary by city: PyCon Chicago was about $100/day, and the Iceland sprint was about $200/day. You can avoid that by buying food and drink at a supermarket which are reachable by public transport. Conventions are vacations for me so I voluntarily spend quite a bit around town.
Vilnius was unusually cheap. The public bus from the airport cost 1.10 litas (about $0.30 US). I thought the hotel was unusually cheap - the venison (deer) plate was 35 litas ($11 us) and 0.5 liters of beer 9 litas ($3 us). The hotel was expensive - prices in town were around 25 litas for a meal and 4.5 litas for a beer.
Conferences should have water and coffee available ALL THE TIME. The PyCon organizers tried to do this but the hotel staff sometimes cleared the service. At EuroPython coffee was available all day but water only rarely; the hotel had no water fountains, none at all (are water fountains an American thing?).
Vilnius is not a wealthy country. Our hotel seemed to be the center of the "jet set" for Lithuania. The casino in the hotel basement was full of locals spending flashy money and the stip club across the street the same (so I am told).
Bars close whenever they feel like, as do restaurants. We had to leave a diner/breakfast place at 7am because they were closing. The casino was open 24 hours a day but to get in you must give them all your information and they take your picture. I think I mostly thwarted them with my state drivers license and a bad picture. I didn't gamble - the rest of the hotel barstaff went on strike but the casino did not.
A Vilnius taxi ("taksi") costs twice as much if you hail one on the street instead of calling. This is the local law. So if you need a cab have the hotel call one for you.
I was worried about attendees English (mostly for my presentation). The ESL (English as a Second Language) English was as good at EuroPython as at PyCon. Also, the material being technical python stuff most of the written content is understandable even if you don't speak the language (I can read Brandl's PyPy talk just fine and I know zero German).
PyCon is about 3/4 American and 1/4 other. EuroPython was the reverse.
If you are standing in a group of people and two of them have speaker's badges then ALL of them will have speaker's badges. This isn't because of elitism; it is because the speakers tend to speak everywhere so they already know each other.