TRENTON -- It was a key voting day that started just after noon -- and didn't end until well after midnight, with the state Assembly passing a surprise sales tax/gas tax deal cut with Gov. Chris Christie.

Here are seven things that happened during a marathon Statehouse session Monday, including votes on the state budget, pension reform, gun control, and more:

1. An unexpected sales-tax agreement

Democrats spent months pushing for a plan replenish New Jersey's nearly broke Transportation Trust Fund -- which pays for new transportation projects -- by raising the state's gas tax by 23 cents.

Some Republicans said they would agree only by trading the hike for a reduction in New Jersey's estate tax. Other GOP lawmakers said they would oppose it either way.

But after hours of negotiating Monday, Christie, a Republican, and Assembly Speaker Vincent Prieto (D-Hudson) emerged around midnight with something else entirely: a deal to counter the hike by reducing New Jersey's 7 percent sales tax to 6 percent by 2018.

Members of the state Senate apparently weren't on board and left without a vote. But the Assembly approved the proposal just before 1 a.m., despite fierce opposition from Assembly Transportation Committee Chair John Wisniewski (D-Middlesex).

"What we're doing tonight is wrong," says Wisniewski in late night floor speech opposing surprise tax deal pic.twitter.com/Ili6wGXWOz — Sal Rizzo (@rizzoTK) June 28, 2016

Christie, meanwhile, held a late-night session with reporters championing the agreement outside his office:

2. Passing the state budget

Christie has until Friday to sign a balanced state budget. And both the Senate and Assembly took only minutes Monday to pass a $34.8 billion version proposed by Democrats.

Now, their version heads to the governor, who is likely to make some changes before signing it.

3. No override on Christie open-space veto

Senate Democrats and a handful of Republicans were about to vote to override one of Christie's repeated vetoes of legislation to preserve open space, farmland, and historical sites in New Jersey.

But the governor, who has never been overridden, struck a last-minute deal.

4. Pension proposal moves forward

The Assembly voted to place a controversial referendum on the November ballot asking New Jersey voters to commit to spending billions of dollars to repair the state's public worker pension system.

Now, it's up to the Senate to give final approval to putting the question before voters.

5. Battle over handgun carry permits

In their ongoing battle over New Jersey's tight gun control laws, Democrats sent Christie a bill that would more strictly define the "justifiable need" residents must show to obtain a permit to carry a handgun in the state.

The governor, though, is likely to veto the measure.

6. 'Smart gun' bill heads to Christie

In another firearm-related vote, the Assembly sent Christie a bill that would revive personalized handguns, or "smart guns."

But, again, the governor is expected to reject it.

7. No override vote on gun bill yet

In yet another firearm-related vote, the Senate was supposed to attempt to override Christie's veto of a bill to make sure people convicted of domestic abuse in the state are stripped of their guns.

But with one state senator not present, the vote was postponed to Thursday.

NJ Advance Media staff writers Claude Brodesser-Akner, Susan K. Livio, Samantha Marcus, and S.P. Sullivan contributed to this report.

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.