Here's a quick thought for the day from Mark Kinzer from his breathtakingly amazing book Postmissionary Messianic Judaism (seriously - it is currently my top book of the decade so if nothing better comes along before the end of the year it wins the Robin's best read 2000-2009 award!)
So here's the brief thought. It is often said that there is a geographical movement in Acts away from Jerusalem: From Jerusalem, to Judea, then Samaria, then the ends of the earth. This move is invested with theological freight (Acts starts in Jerusalem and ends in Rome - a move away from a Jewish-shaped faith).
Kinzer argues that the movement in Acts is actually complicated. "It does not begin in Jerusalem and then progressively and steadily radiate outward. Instead, the story continually reverts back to Jerusalem" (Acts 9:26-29; 11:2, 27-30; 15:2; 18:22; 21:17-23:11).
He suggests that the Acts 1:6-12 leads the reader to extect a narrative arc starting and ending in Jerusalem. "The drama would not reach its satisfying conclusion until the arc was again completed and the narrative returned to Jerusalem. Thus Luke deliberately composed an unsatisfying ending [Acts 28 is an odd end] so that we would know that it was not really the ending."
I think that this is a really interesting suggestion and my reading of Luke-Acts (which is not based on scholarly research but is based on lots of readings) inclines me to think that he is right.