Barcelona is a transport hub with an international airport, Barcelona–El Prat Airport, about 17 km from the center of the city.
Taking a cab from/to the airport is not expensive (~30€) but Barcelona airport also has metro, bus and train (Rodalies) connections. Getting to the city in public transport is cheaper (~6€) but it also takes more time. If you arrive to the terminal T1 (most probably) you have metro and bus available but you'll have to buy an special ticket (the T-10 does not cover it). If you are taking a low cost flight you'll arrive to the T2 terminal (most probably, if it's not Vueling), the metro does not arrive there, but you have the train (Rodalies) as an option.
Barcelona also has an extensive motorway network and a high-speed rail line with a link to France and the rest of Europe.
The local public transport is also outstanding, including metro, bus, train (Rodalies and FGC) and tram facilities. An integrated ticket valid for all public transportation in Zona 1 (inner city zone) can be purchased at any metro station in automated machines. It allows you to travel within the network with no restrictions at a very affordable price (90 cents per ride) using a 10-ride ticket (T-10). You can also share a T-10 with several people as long as you all stay together during all the ride. You can even jump from one to another (eg. bus-metro or bus-bus) within an 1h 30m window allowance. Although there's also some special visitor's tickets, we still think that the T-10 is the cheapest and easiest way to go.
If you plan to do a lot of trips within your staying in Barcelona (not probably if you are attending the trainings, conference and sprints), you can buy one of the Hola BCN! travel cards. This Barcelona transport pass offers unlimited journeys on metro, bus (TMB) and the rest of the Barcelona public transport network over 2 (48 h), 3 (72 h), 4 (96 h) or 5 (120 h) consecutive days, with one ticket.
Barcelona has no UBER or similar services, so if you want to get a car, you'll have to use a Taxi. They are not extremelly expensive, but still it's the most expensive way to travel by public transport, and transit at peak hours might be a problem.
Further useful information links:
https://en.wikipedia.org/wiki/Barcelona
https://www.lonelyplanet.com/spain/barcelona
http://wikitravel.org/en/Barcelona