"act tonight" is correct and usable in written English.
You might use this phrase to exhort someone to take action as soon as possible, as in "We need to act tonight if we are to have a chance at success."
He sneaked off to London for a two-week run at the Tricycle Theater and now, back in New York, is resuming his act tonight.
A spokeswoman for the president said last night that the White House had just received the recommendation and would not act tonight.
With his hands on his hips and a blunt, sheriff-like demeanor, Lt. Col Robert Waltemeyer politely read the riot act tonight to 30 religious, tribal and community leaders.
Kraftwerk may be the headline act tonight but the festival's raison d'etre is to promote and commission original and new work, which tonight is provided by the minimalist composer Steve Reich.
Except as to the particular shape in which it was staged, and as to some of its accesseries, the final act tonight in the progress of the Franchise Bill came out pretty much as had been foreseen - namely, in the elimination from the bill of the immediate application alike of P.R. and the alternative vote.
Last night I gigged at a new act night.
9.43: And of course, in final and privileged position for the phone vote, Susan Boyle was the last act this evening.
Some things don't change though – Coldplay, awarded best live act last night, were also double winners 10 years ago.
A statute that is likely to play an important role in any potential criminal case is a provision of the Commodity Exchange Act, 7 USC § 13(a)(1).
And even Obama got into the act last night, mocking a decades-old rule that forced dairy farmers to demonstrate their ability to control milk spills as an exemplar of the ridiculousness of government regulation.
