10. Brendon McCullum's Twenty20 Innings of 158*
It was in the first ever match in the Indian Premier League (IPL), back in 2008, that New Zealand wicketkeeper-batsman Brendon McCullum smashed the highest-ever Twenty20 score.
Of all the current records in T20, which is still less than a decade old, McCullum's 158 not out seems the most difficult to surpass.
