When we travel, it's common for hackerspace members to reach out to other hackerspaces located in our destinations. It's a great way to meet the locals, share ideas, and learn how other people run a hackerspace. Interlock has entertained guests from all over. Sometimes travelers will email us saying they are doing a tour of hackerspaces in the region and wanted to stop in for a night. When we're available, we're happy to entertain at the space and even take them out for a drink. I remember one visit from a group travelling first to New York City (NYC Resistor, Alpha One Labs), going up through Syracuse (SIG 315), to Rochester (Interlock) and ending up in Toronto (Hacklab). Our members have visited spaces all over the country; Florida, Texas, California, North Carolina, and Washington DC are a few that I can remember. There is even a hackerspace passport that Noisebridge started where you can get it stamped at the various hackerspaces that you visit.
Hakkavélin
Myself and another member recently visited Iceland for New Years for just over a week and the day after we landed, we jumped on the Hakkavélin IRC channel to reach out to see when open hours were and if we could arrange a visit. While the space wasn't opened due to the holidays, Sigurður óskarsson was kind enough to meet us at the hackerspace to take us out to a cafe in town. We talked shop a bit, discussing projects people were working on and history of each others' spaces, along with operational details like how they handled membership and how much they charged.
We learned about their door system which consisted of a full computer sitting outside of the space controlling the door lock. In order to get in, you have to figure out how to use the console in a hackery way. As I understand it, there's also an IRC bot which controls this door if you message the right user. Located inside the University of Reykjavik, the group is just outside of the downtown area in South Reykjavik. With only four hours of light this time of year, I wasn't able to get a good look at the university but the buildings I saw were pretty with huge glass walls.
If you have never considered looking up a local hackerspace on your vacation or business trip, I would strongly recommend you consider it next time. It's a great way to meet like-minded folk in different locations.