Toronto is trying to rewrite their history, Cleveland has re-tooled through trades and Boston's cooling off as the NBA enters the final seven weeks of the season following the annual all-star break.
The Toronto Raptors lead the Boston Celtics in the Eastern Conference by two games while the Houston Rockets sit atop the West with the best record in the league at 44-13.
The NBA regular season resumes on Thursday after Sunday's entertaining all-star game which saw LeBron James score 29 points, including the go-ahead layup with 34 seconds left, as his hand-picked team rallied to beat Team Stephen 148-145.
James' Cleveland Cavaliers square off against the Washington Wizards in one of six games on Thursday.
The Cavs are seeking to make the NBA finals for the fourth consecutive season as they appear to have resurrected following a mid-February roster overhaul through trades.
"Championships is what I play for," said James, who is looking for his eighth straight finals appearance. "We just added four new guys before the break, and we have a lot of work to do.
"Winning championships is what it's all about. That's what this league is all about and hopefully at the end of the road then I have the Cavs there to be in a finals representing the East.
"So that's my goal. Getting back," he said at the all-star game in Los Angeles on the weekend. "I'm looking forward to getting back to our guys. I know they're excited, and that's going to be my mindset."
- Raptor evolution -
The Raptors were eliminated in the second round of the playoffs last season after making it to the conference finals the year before. In 2015 and 2014 they didn't get past the first round.
"It's an evolution of growth and making us a better team," said Toronto's DeMar DeRozan. "So I love it. Obviously it's showing, and we've been winning at a high level this year."
DeRozan said another reason for their success is the play of their younger guys coming off the bench.
"Our bench is everything," he said. "Our bench gives us older guys an opportunity to not play in the fourth quarter and to rest.
"It's great to be able to sit back and cheer those guys on while they go out there and pull out victories."
The Celtics are 18-15 in their last 33 games after starting the season 22-4.
Veteran Al Horford, 31, said Saturday in Los Angeles, that the Celtics can't afford to get ahead of themselves.
"What I try to emphasize to (teammates) is embracing the now," centre Horford said. "So I just think it's embracing and taking advantage and doing the best you can with the group that you have."
In the West, Houston has the best record in the league but sit just a half game ahead of the defending NBA champion Golden State Warriors.
"We set a goal," said Rockets star guard James Harden. "We wanted to be the best team and come out this year with the championship.
"We got the right group around us. You can't guard us."
The Rockets went into the all-star break on a 10-game winning streak and this marks the first time in franchise history Houston is on top at the break.
"We got a long way to go but we are going to continue to try to get better and continue to grow and make a run in the playoffs," Harden said.