The centre of Oslo is very small, and the best way to see it is on foot. But it is also easy to get around Oslo with public transport. The T-bane (Metro, underground) and buses cover most of the centre and surrounding area, and in the centre you can get on the tram, a somewhat slow, but efficient way to travel, with very frequent stops in the city streets. Included in the ticket system in Oslo are also ferries going out to some of the islands in the Oslo fjord. If you plan to do more than two journeys in a day, a 24-hour ticket is a good idea. You can buy tickets at the machines at the T-bane stations or in some kiosks (Narvesen, 7-Eleven, Deli De Luca and Mix). Single tickets are also sold on board the buses, but then they are more expensive, so make sure you have your ticket beforehand, or download the Ruter App to buy tickets. Note that you have to validate your ticket before you travel. This is done at the T-bane station or when you enter the bus or tram. The nearest stop for the festival is Grorud on T-bane route 5 Vestli, eastbound; and T-bane route 4 Vestli westbound; or Grorud T for buses.

Go to https://ruter.no/en/ to plan your journey and see prices.
Ruter mobile App: https://ruter.no/en/mobile-apps/

Taxi in Oslo (and the rest of Norway) will seem expensive for most people from other countries! You will find taxi stands all over the city, or you can hail one on the street. There are several taxi companies, and the prices may vary - it would be a good idea to ask for an estimate before you enter one. Typically, the fare from the city centre to Grorud would be around NOK 400 in the daytime, around 500 at night. If you stay out late and don’t want to spend on a taxi, there are night buses, and one bus route operating 24 hours a day: Route 31 Snarøya – Grorud.

If you drive in Norway, note that cars coming from the right have the right of way if nothing else is indicated by signs. This can be confusing when you drive on what seems like a main road and have to stop for cars from narrow side streets, so look out. In Norway we stop for pedestrians, and they will walk! The alcohol limit for driving is 0.2, so leave that glass of wine until you’ve parked the car for the day.

While we’re on the subject of alcohol: Beer, cider etc. up to 4.7 % can be bought in supermarkets, stronger drink only available at Vinmonopolets outlets. You will find them at most shopping centres, like Grorud Senter. You will probably find that alcohol is also expensive in Norway, and it can be worth noting the quota you are allowed to bring into the country: http://www.toll.no/en/goods/alcohol-and-tobacco/quotas/