The rules of the game if you want to file an age discrimination case in Federal court include filing a discrimination complaint with the Equal Employment Opportunity Commission. Then you have to wait two months before you can bring the lawsuit, giving the EEOC an opportunity to investigate and possibly resolve the claim. But there is another way: Section 1983.
The Supreme Court has never taken up this issue, but in the Second Circuit, the district courts for the most part are allowing plaintiffs to litigate their age discrimination claims under the Equal Protection Clause of the Constitution, enforceable through Section 1983. Other Circuits have held that you can't do this, because the Age Discrimination in Employment Act is sufficiently comprehensive to preeempt Section 1983 (the general civil rights law which allows you to enforce your federal rights in court). See, e.g., Zombro v. Baltimore City Police Dep't, 868 F.2d 1364, 1366-67 (4th Cir. 1989) (availability of the ADEA's detailed procedures forecloses age discrimination claim brought under § 1983 because a plaintiff may not "cavalierly bypass the comprehensive process fashioned by Congress in the ADEA"). But for the time being, in the Second Circuit, you can litigate both under the ADEA and Section 1983.
This issue was brought to life once again recently in Shapiro v. New York City Department of Education, 2008 U.S. Dist. LEXIS 46327 (S.D.N.Y. 2008), decided on June 16. My office co-represented the plaintiffs in Shapiro. In that case, some of the plaintiffs did not file EEOC complaints. Their only remedy for the age discrimination against their government employer, then, was Section 1983. This statute holds that state actors who violate your civil rights can be sued in court for damages. There is no damages cap under Section 1983, which also offers punitive damages and attorneys' fees. It also has a longer statute of limitations than the ADEA: three years to 300 days.
Why can plaintiffs sue both under the ADEA and Section 1983? Because the Second Circuit held in 1993 that race and gender discrimination, normally litigated under Title VII of the Civil Rights Act of 1963, may also violate the Equal Protection Clause. That case was Saulpaugh v. Monroe Cmty. Hosp., 4 F.3d 134 (2d Cir. 1993), which held that Title VII did not preempt a § 1983 claim for gender discrimination in violation of the Equal Protection Clause of the Constitution. As the district courts in the Second Circuit have held that age discrimination claims against the government may be litigated under the Constitution, see, e.g., Purdy v. Town of Greenburgh, 166 F. Supp. 2d 850 (S.D.N.Y. 2001), Judge Rakoff adopts the reasoning in those cases and allows the plaintiffs' Section 1983 claims in this case to go forward.