An A380 will be at ORD on or before the following:

When LH upgrades to 380 (FRA then MUC).
When BA upgrades to 380.
When KE upgrades to 380 (as of now, the most likely scenario).
When QR starts ORD-DOH.
When EK starts ORD-DXB.
When AA does something intersting at ORD (outside of an RJ).
When UA does something intersting at ORD (outside of an RJ or shift to CO).
When ORD gets nonstop service to Berlin (forget the new code).
When ORD gets nonstop service to ATH.
When ORD gets nonstop service to TLV.
When ORD gets nonstop service to GLA.
When ORD gets nonstop service to BHX.
When ORD gets nonstop service to SVO/DME.
When ORD gets nonstop service to CAI.
When ORD gets nonstop service to BOM.
When ORD gets nonstop service to NGO / KIX/ MNL / BKK / SIN / MNL / TPE.
When NZ starts ORD-AKL on 787.
When QF starts ORD-SYD on 787.
Pigs fly.

Which will happen first, if any?