Adele's blockbuster album "21" has enjoyed another sales surge this week, and will likely finish the week at No. 1 on the Billboard 200 albums chart for a 24th week, according to Billboard.  The official chart will be released next Wednesday.  If "21" does reach the chart's summit again, it would mark the longest time at the top spot since Prince's "Purple Rain" spent 24 weeks at the top in 1984 and 1985.  It would also be just the eighth album in history to spend six months at the top of the Billboard 200.