It's unusual in that they announced last Friday to take it on, and it carries some potentially big ramifications as plaintiffs are arguing that subsidies are unlawfully being provided to those who purchase their mandatory helath insurance through the federal exchange, rather than through a state exchange.
They say that under a literal reading of the law, subsides are available only in states that established their own exchanges.
Therefore, they contend, residents of some 36 states are ineligible. A ruling in favor of plaintiffs could have the effect of killing Obamacare entirely, although other outcomes are possible. It's also unclear as to how such a ruling might affect Oregonians, as even though we're now being required to switch over to the federal exchange, Oregon is unique in that it did, in fact, establish the Cover Oregon exhange - it just never worked.
Of course, it all becomes moot if SCOTUS rules against the plaintiffs.