I recall back in the day (80's) being deeply involved into music making tapes exchanging tapes many times not knowing the names of the songs & artists nevertheless the excitement of just getting the jams and  enjoying the jams was enough to satisfy the vibe .Today with options such as sound hound internet radio and other sources to obtain information of music in general  makes it all so much easier ... however I rather relive the way of getting those jams, tape - tape  friend - friend .....

it happened to me all the time! it's incredible how sometimes it took ages to find out who was who  

I've had songs that I taped in the 80's that I've just recently figured out the artists thanks to the internet. It's like discovering them all over again.

The new Nokia Lumia phones have a Music Recognition App which does this exactly. Just hold the phone with the app running towards the speaker playing the music. The phone  "listens" to it and identify the song in few seconds.

I tried it with my Nokia 820 and works beautifully. It even recognized a 1983 song from an Indian regional language instantly. The song quality was poor, converted to MP3 from cassette and it was playing through a laptop speaker!