Astronomers chase around the world to observe rare events such as solar and lunar eclipses. Last past new moon (January 15, 2010) astronomers went to India, Uganda and China) to watch the annular solar eclipse (longest on record - it seems)
Likewise Music Rasikas chase their favorite singers to listen to their concerts (Rasikas who follow artists from concert to concert are called groupies in the US). People like me, on the other hand chase after a particular song. Normally in each concert (especially in Carnatic music), there is a main piece in which artists play a raaga aalapana, violin player play a solo piece, sing a kriti, do kalpanaswaram (do swarams) and a niraval (picks a line of lyric from the kriti piece and is played in different tempos and the artist shows his/her imagination and artistic mettle). According to Wikipedia
Improvisation in raga is the soul of Indian classical music - an essential aspect. "Manodharma sangeetham" or "kalpana sangeetham" ("music of imagination") as it is known in Carnatic music, embraces several varieties of improvisation. The main traditional forms of improvisation in Carnatic music consist of alapana, niraval, kalpanaswaram, ragam thanam pallavi, and thani avarthanam
We will try to illustrate with three videos and an audio files by two different singers singing the same song. First by Priya Sisters.
Starting with Alaapanaa with a violin solo
Now come the kriti
Now we have an audio recording of Smt. Vidya Subramnanian's rendition of the same song during her 2005 Pallavi Concert.