A Russian band called “The Live Voices” have uploaded a video where they perform the Dota 2 main them in accapella. The band specialises in recreating different songs/music in their own accapella style.
The video is an extremely impressive recreation of the theme. Arriving just after the end of TI5, it serves to summarize the impressions left by the tournament. The band have their own youtube channel, https://www.youtube.com/user/TheLivevoices/, where there are many other renditions of popular songs and soundtracks performed in accapella.