Blinking LED at two speeds using 555 Timer
Flash one: b-----b-----b-----b-----b-----b-----b-----b
Flash two: ---b-----------------b-----------------b---
time       0     1     2     3     4     5     6     7


...Assuming you want it to repeat.

Haven't really thought through triggering the start of timer two so it's properly offset from timer 1, and so it does not drift. Might involve a 3rd timer or a clever trick I'm not thinking of - the third timer seems a straightforward enough method, but the 555 inspires so many clever tricks I'm sure someone has a different way. You could also use some logic and the trigger/reset pins. Remember that there are 556's if you are using more than one.

If you are up for some additional components you could use the output of timer 2 to double the charge rate on the timer 1 capacitor (though due to timing limitations you either need some more externals or a method that inverts the sense of the output so that you double the charge rate for 1 second and not for 2 seconds. "Stock" 555 circuits don't do duty cycles below 50%, but as usual there are ways around that...