Nushi,

you may want to reverify your project options. I just changed to NRW to test and immediately got RICE work.

Are you getting messages in your client log to say there is none available, sending other work?

As Sekerob said, check your options... you can also create another Device Profile on the MyGrid page, under Device Manager->Device Profiles.

Besides the default profile (which I leave with all tasks selected, plus the 'If there is no work ...' and 'Please opt me in ...' boxes checked), you can use the links there to 'Create A New BOINC Device Profile' for "home" "work" and "school."

Use one of those 3 extra profiles to select only the NRW task, UNcheck the 2 'If there is no work ...' and 'Please opt me in ...' boxes (because DDDT-2 might start before NRW ends).
Set your Advanced options below that, then click the Save button.

You might consider increasing the 'cache' in the "Workunit Cache Settings" section while making the profile to, say, 0.5 to 1 day (I think the default is 0.2 days), so if WCG's servers go offline for 4 or 5 hours (accidents happen; hardware breaks; et cetera), your devices don't 'run dry'. Also consider that in BOINC the Advanced->Preferences setting on the 'network usage' tab, "Additional work buffer" will override that Device Profile setting.

You can set each of your devices to use that profile on the Device Manager page by selecting the device name (click its link in the Device Names column), choosing the new Device Profile from the picklist, then the Save button. Repeat for each device.

The next time BOINC updates with the WCG Project (usually happens when BOINC requests more work, but you can force it to update by selecting the World Community Grid project name on the Projects tab, then clicking the Update button), it will start using the new profile.
You can confirm that on the Messages tab... e.g. it will change from saying 'Computer location: default' and tell you instead 'New computer location: home' (or whichever home/work/school Device Profile you created and used for RICE).

If you participate in beta testing with your "default" profile, the new profile should automatically get added with a check mark on the Beta Testing page, but you might want to double-check that setting.

Then you can 'for sure' force all your devices to run only RICE (NRW) work. There is a way you can actually name the profile RICE, but it requires a 'kludge' to get your devices to use that profile. Still, it IS possible to concentrate all devices on 1 task using the tools the WCG project gives us on the MyGrid page (it's just not accessible during stats updates, twice/day... which typically takes less than an hour each time).

I rather think it was the "If there is no work available for my computer for the projects I have selected above, please send me work from another project." (SIC) box.

I've seen my quads get 2 or 3 work units, then while those are still downloading BOINC requests more... which means there were not enough work units from the RICE task in the hopper to fulfill the first request, so it had to ask again. It seems to me that if that box was checked, it would have just given me some work units from 'another' task to go along with the RICE WUs.

Or if it's really enormously unbelievably important to you, select another boinc project, with resource share low (like 25 or so), and give WCG a large(r) resource share (like 1000 or so) in addition to the above hints. This prevents running dry.

Not everyone has DDDT2 "A"-type capable machines

But I'm not crunching Rice either at the moment so I'm not guilty here