diff --git a/hydra/modules/sysadmin/services.scm b/hydra/modules/sysadmin/services.scm
index 334986b..39a1ea6 100644
--- a/hydra/modules/sysadmin/services.scm
+++ b/hydra/modules/sysadmin/services.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix system administration tools.
 ;;;
-;;; Copyright © 2016-2022 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016-2023 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2017, 2018, 2020, 2022 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2022 Leo Famulari <leo@famulari.name>
 ;;; Copyright © 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
@@ -419,7 +419,21 @@ collection instead."
                 (period 7200)
                 (priority 2)
                 (systems '("x86_64-linux"))))
-            #~())))
+            #~())
+
+     ;; Bonus specs: projects other than Guix.
+
+     (specification
+      (name 'guile)
+      (build '(manifests "build-aux/manifest.scm"))
+      (channels
+       (list (channel
+              (name 'guile)
+              (url "https://git.savannah.gnu.org/git/guile.git")
+              (branch "main"))
+             %default-guix-channel))
+      (priority 5)
+      (systems '#$systems))))
 
 
 ;;;