Flowers are in full bloom in front of the U.S. Capitol.

The federal government is expecting to collect around $2.7 trillion in tax receipts this fiscal year.

That would be an all-time record, outpacing the 2007 pre-crisis peak of $2.5 trillion. But some economists are predicting an "April surprise," with much higher than expected revenues pouring into federal coffers because of outsized gains by the wealthy in 2012.