Can anyone explain in words what this formula is doing?

=IFERROR(INDEX([RefHidden_120112.xlsm]Ref!$CA$5:$CB$22,
MATCH(1,IF(TODAY()>=[RefHidden_120112.xlsm]Ref!$BY$5:$BY$22,
IF(TODAY()<=[RefHidden_120112.xlsm]Ref!$BZ$5:$BZ$22,1)),0),
MATCH(B92,[RefHidden_120112.xlsm]Ref!$CA$3:$CB$3,0)),1)

Thanks.

Dan