Several electrical outlets in my house have suddenly stopped working. In the same room, one outlet continues to function while the other one died. I checked the circuit breakers and they are all on. Any ideas?

Loose connections. Probably due to backstabbing rather than pigtailing in the outlets. Take apart an inspect. Another possibility is a GFCI somewhere.

Several electrical outlets in my house have suddenly stopped working. In the same room, one outlet continues to function while the other one died. I checked the circuit breakers and they are all on. Any ideas?

Have you done any work in the house lately ? Hang any pictures, nail any drywall,etc.
You see where I'm going with this.
Do like KISS said and remember that it could be in an outlet that is working.

Remove one of the non-working outlets. If it is wired using the little holes in the back, remove and put under screws. This is what KISS is referring to about "back stabbing". This type of wiring is famous for developing bad connections after a period. Do all outlets and switches. The bad connection may be in one of the non-working outlets or it may be in the last working outlet.

Regarding some outlets working and some not in the same room. House wiring circuits are not always aligned by room. There may be different circuits feeding different outlets in the same room. Also Turn off main breaker at service enterance and check for corrosion or contaminant where breaker meets service box bar.