What Alex has learned so far (since January) on his electric guitar:

Metallica - The Unforgiven, Enter Sandman, beginning of Master of Puppets, beginning of Seek and Destroy, beginning of One, beginning of Welcome Home (Sanitarium)

Ozzy - beginning of Crazy Train,

Black Sabbath - beginning of War Pigs, beginning of Paranoid, Iron Man

Led Zeppelin - beginning of Stairway to Heaven

Cream - parts of Sunshine of Your Love

Deep Purple - beginning of Smoke on the Water

Plus he made up his own tune and figures out things like Happy Birthday